In digital communications systems, transmission of data over various media can take many physical forms, and follow any of a large number of protocols. A common protocol for the transmission of data in the form of packets is the Ethernet protocol, described in IEEE Standard 802.3. An overview of the Ethernet protocol, including a review of the various media forms is given in “Ethernet Technologies”, published electronically by Cisco corporation. The original Ethernet was developed by Xerox in the 1970s as a coaxial cable network using a carrier sense multiple access/collision detect (CSMA/CD) protocol, providing a bus-like local area network (LAN) that allows a number of computers to share access to the same coaxial cable. Since then other media types have been introduced, and at present the Ethernet protocol is used primarily over twisted pair copper cable, and fiber optic cable. The article. “Techfest Ethernet Technical Summary”, section 4.0 “Ethernet Physical Layer Specifications” provides a summary of the various physical layer specifications defined for Ethernet.
Because of the high performance/cost ratio, compared with other technologies, Ethernet is increasingly being used to provide basic digital packet communication in many networks, and for many applications beyond the original LAN of computers of the 1970s.
While the early implementations of Ethernet were limited to a broadcast oriented bus structure, with access to the bus being controlled with the CSMA/CD protocol, almost all recent versions of Ethernet rely on dedicated full-duplex links with point-to-point transmission of Ethernet frames (packets). In Metropolitan Area Networks (MAN) and Wide Area Networks (WAN), that are based on Ethernet switching, fiber optic cable is common, while in Local Area Networks (LAN), a hubbed or switched Ethernet architecture based on 10BaseT, 100BaseT and 1000BaseT is more common. In these, the Ethernet frames are transmitted over unshielded twisted pairs (UTP) at rates of 10, 100, and 1000 Mb/s respectively. UTP cable is generally more economical and easier to install than coaxial cable or fiber optic cable.
Digital technology is being applied in many industries. The conventional Cable Television Systems (CATV), originally developed with analog technology for the distribution of television signals to homes (and to a lesser extent, to businesses), are generally based on frequency division multiplexing (FDM) of channels, where each FDM channel carries a television program channel. Recently, the cable television industry has developed means to use digital technology in the distribution not only of television signals (digitally encoded television) but also in providing digital services such as MAN and internet access over an enhanced cable infrastructure, while generally maintaining the FDM structure of the systems. One such digitally enhanced system is described in U.S. Pat. No. 6,763,025 “Time division multiplexing over broadband modulation method and apparatus” issued to Leatherbury, et al.
Thus, a situation has developed where digital networks based wholly or partially on the Ethernet protocol are distributed in a number of different physical forms. For example, a household may subscribe to digital television services, distributed over coaxial cable to and within the dwelling, while the same household may also subscribe to internet. Internet access that may be provided to the dwelling over a coaxial cable or a Digital Subscriber Line (DSL). The subscriber may wish to make internet access available to computers in several rooms and thus requires the installation of a LAN. An Ethernet LAN based on UTP wiring is one available method today. At the same time, TV reception from the cable television system may also be required in more than one room, conventionally achieved by extending the coaxial cable from a splitter to these rooms.
FIG. 1 illustrates a typical home wiring, providing television, telephone, and internet services. FIG. 1 shows a dwelling 10 comprising: a cable splitter 12; two television sets 14 and 16; a DSL splitter 18; two telephones 20 and 22; a DSL modem 24; a LAN 26; and two personal computers 28 and 30. The LAN 26 may include a hub or router 32, connected by UTP cables 34 to the DSL modem 24, and to the personal computers 28 and 30. The telephones 20 and 22 are connected to the DSL splitter 18 over an in-house telephone wiring 36, and the television sets 14 and 16 are connected to the cable splitter 12 over in-house coaxial cables 38. The signals for the television sets arrive from outside the dwelling over a coaxial cable 40, while the signals for the telephone and internet services arrive over a subscriber loop 42. The DSL splitter 18 is connected to the DSL modem 24 over a pair 44. Typical other equipment not shown for simplicity include digital television converters (set top boxes), and the different types of connectors and jacks associated with the different types of cables. It should be noted that the coaxial cables 38, 40, and the in-house telephone wiring 36, are typically provided when a new dwelling is built; UTP cabling is typically not included by default.
Without prejudice as to the future convergence of digital services into a single system on the service provider side, it would be desirable to minimize the need for deploying multiple wiring schemes within the dwelling to provide such services. In the case where coaxial cable distribution is already a given, it would be desirable to avoid having to add a UTP cabling distribution for the LAN. Further, it would be desirable to avoid separate physical or logical partitioning of these networks because it causes additional network management complexity driven by the multiple logical or physical networks, and multiple technologies involved.